There is no problem with adding the baking soda with the Proform C. The filter bacteria converting ammonia to nitrite and nitrite to nitrate produce a lot of acid which will consume the KH, but the Aquascapes Dry Bacteria, is not a source of the beneficial filter bacteria. I think it is designed for use in the aquascape ponds to digest the solids, which are trapped in the gravel, in an anaerobic environment, like a septic tank. Anaerobic digestion has no place in a koi pond.
Zone 7 A/B
Keep your words sweet. You never know when you may have to eat them.
Richard